Another interesting name on the list of participants is Roberto Unger, who is a well-known Brazilian politician and besides that a professor for law at Harvard Law School, and author of multiple books on social and political theory. He apparently has an interest not only in the laws of societies, but also in the laws of Nature*. And finally let me mention George Musser was also at the workshop. George writes for Scientific American and is author of The Complete Idiot’s Guide to String Theory. He turned out to be a very nice guy with the journalist's theme "I want to know more about that."

Talks (their)

Now let me say a word about the talks. First, and most important, all the talks were recorded and are available on PIRSA here. The talks on the first day were heavily philosophical. I will admit that I often have problems making sense of that. Not because I don't have an interest in philosophy, but because one frequently ends up arguing about the meaning of words which is, at the bottom of things, a consequence of lacking definitions and thus a waste of time. Yes, my apologies, I'm, duh, a theoretical physicist with some semesters maths on my CV. If I don't see a definition and an equation, I get lost easily. In some cases it seems the philosophers imply some specific meaning that they just never bother to explain. But in other cases they'll start arguing about it themselves, and that's when I usually zoom out wondering what's the point in arguing if they don't know what they're arguing about anyway.

The most interesting event on the first day was arguably Lee Smolin's and Roberto Unger's shared talk "Laws and Time in Cosmology". Let me add that I've heard Smolin talking about the "reality of time" several times and I still can't make sense of it. The problem I have is simply that I don't know what he's talking about. This recent talk didn't change anything about my confusion, but if you haven't heard it before, you might find it inspiring. Unger's talk is very impressive on the rhetorical side. Unfortunately, it made even less sense to me than Lee's talk. For all I can see, there's no tension neither between a block-universe and a notion of simultaneity nor between a block-universe and causality, as I think I heard Unger saying (thus my question in the end). Point is, I don't understand the problem they're attempting to address to begin with. I see no problem. As Barbara Streisand already told us "Life is a moment in space" and "In love there is no measure of time." Consequently, a universe where time is real must be loveless. I don't like that idea.

On that note, let me recommend Julian Barbour's talk "A case for geometry". Julian is a charming British guy and he has his own theory of a lovely, timeless universe. I don't buy a word of what he says, but his talk is very accessible and fun to listen to. It makes your head spin what he's saying, just try it out, it's very intriguing. I am curious to see how these ideas will develop, it seems to me they might be on the brink of actually making predictions. (A somewhat more detailed explanation of his ideas is here, audio becomes audible at 3:30 min.)

On the second day, we had several talks discussing concrete proposals for how one could think of the laws of Nature off the trodden path. You probably won't be surprised to hear that one of the suggestions is that of "Law without Law: Entropic Dynamics" by Ariel Caticha. It is not directly related to Erik Verlinde's entropic gravity, but certainly plays in the same corner of the room: exploiting the possibility that fundamentally all our dynamics is simply a consequence of the increase of entropy. Ariel's talk however isn't really recommendable, it sits on a funny edge between too many and too few details.

Another approach is Kevin Knuth's who put forward in his talk "The Role of Order in Natural Law" the idea that on the basis of all, there's order - in a well-defined mathematical sense. I can't avoid the impression though that even if this worked out to reproduce the standard model, it would merely be a reformulation. Kevin's talk was basically a summary of this recent paper. And Philip Goyal gave a very nice talk on "The common symmetries underlying quantum theory, probability theory, and number systems." I have a lot of sympathy for the attempt to reconstruct quantum theory, it's just that I don't understand why literally all the quantum foundations guys hang themselves up on the measurement process in quantum mechanics. For what I'm concerned, quantum field theory is the thing, and I'm still waiting for somebody to reconstruct the non-commutativity of annihilation and creation operators.

Finally, let me mention Kevin Kelley's talk "How does simplicity help science find true laws?"Kelley is a philosopher from Carnegie Mellon, and in his talk he explored whether it is possible to put Ockham's Razor on a rational basis. Unfortunately, while the theme could in principle have been very interesting, his talk is not particularly accessible. He assumed way too much knowledge from the audience. At least I get very easily frustrated when technical terms are dropped and procedures are mentioned without being explained, since it's not a field I work in. In any case, I'll spare you the time watching the full thing and just mention an interesting remark that came up in the discussion. Apparently there have been efforts to create a computer software that could simulate a "scientist," in this case for the example of trying to extract a theory from data of the motion of the planets. At least so far, such attempts failed (if anybody knows a reference, it would be highly appreciated.) So it seems, for the time being, scientists will not be replaced by computers.

At the end of the last day we had a discussion session, moderated by Steven Weinstein, wrapping up some of the topics that came up the previous days and some others. One of them is the question about the power of mathematics and if there are limits to what humans can grasp (a theme we have previously discussed here). For a fun anecdote making the point well, watch Steven at 1:13:50 min ("I remember distinctively being in a graduate quantum mechanics class by Bob Wald...") Of course Tegmark's mathematical universe made an appearance as well, another topic we have previously discussed on this blog. For what I am concerned, declaring that all is mathematics may be some sort of unification of the laws of Nature, alright, but it's eventually a completely useless unification. And that brings me to...

Thoughts (mine)

On several occasions at the workshop, I felt like the stereotypical physicist among philosophers, and it took me a while to figure out what I found lacking at this workshop. You could say I'm a very pragmatic person. There's even an ism that belongs to that! If you talk about reality and truth, I don't know what you mean, and I actually don't care. This is just words. I'll start caring if you tell me what it's good for. If you want to reformulate the laws of physics, fine, go ahead. But if you want me to spend time on it, you'll have to tell me what the advantage is. If there's two theories and they make the same predictions, that doesn't cause me headaches. For what I'm concerned, if they make the same predictions, they're the same theory.

What matters in the end about a law or a theory or a model is not whether it's philosophically appealing and not even if there's a rational process by which it's been selected (and btw, what means "rational" anyway), but simply whether it's useful. And usefulness is eventually a notion deeply connected to human societies and values. For that reason I think to understand the scientific method and its success one inevitably needs to take into account the dynamics of the communities and the embedding of scientific knowledge into our societies. (It should be clear that with usefulness I don't necessarily mean technical applications as I have recently expressed in this post.)

Leaving aside that I found this aspect entirely missing to the discussions about the process of science itself and its possible limitations, the workshop has given me a lot to think about. Having said that the pragmatist in me searches for the use in all that enters my ears, I nevertheless have enough fantasy to imagine that some of the themes discussed at the workshop will become central to shaping our thinking about the laws of Nature in the future and thus eventually prove their usefulness. It was a very stimulating meeting and the approaches that were presented are all as bold as courageous. It will be interesting to follow the progress of these thoughts.

*I once made an attempt to read one of Unger's books, What should the left propose? I had to look up every second word in a dictionary, and even that didn't always help. When I had, after an hour or so, roughly deciphered the meaning of a page it seemed to me one could have said the same in one simple sentence, avoiding 3 or more syllable words. I gave up on page 20. Sorry for being so incredibly unintellectual, but to me language is first and foremost a means of communication. If you want to be heard, you better use a code that the receiver can decipher. Friedrich Engels, for example, was an excellent writer...

90 comments:

Thanks so much for your synopsis and take on the conference you just attended of which many of those presentations you mentioned I’ve looked at since. I must say many of them I enjoyed, particularly the one by Unger/Smolin, not that I thought what was said was all that new or revolutionary, yet brings up again what I find important in the inquiry about the foundations as to its usefulness in discovery. I also like your frankness in all this in saying it is this usefulness that stands as being the bottom line for you, as if it works it works. On the other hand I’m the kind of person where saying if it works is not quite enough, which I wouldn’t boast as a better way to look at matters, yet rather the only way I can come to have things understood, which means in the end I don’t feel I understand as much as I’d like.

I recall reading J.S. Bell’s essay on” How to teach special relativity” where he argues that the difference between the Lorentz, Poincare, Fitzgerald approach and that of Einstein’s was found only in their differences of philosophy and style, leaving nothing of a predictive nature to distinguish between them. He suggested that the former approach should be presented to students before introducing Einstein’s way, as the journey to discovery is as important as its destination, which I found to be one of the most profound statements ever made by any scientists, particularly from one as pragmatic as Bell. That what Bell was reminding is if one doesn’t realize the path from which one has arrived someplace, it then becomes more difficult to understand from where to return when things don’t gp right. So this is what I’ve always found to be the utility of foundational research, as to doubt even our most cherished conclusions all the way back to the place from which they were derived.

Just to clarify, the way I refer to "usefulness" it includes the possibility that thinking about something old from a new perspective can open new ways forward. Of course, that it "works" per se is not enough, which brings up the question for Ockham's razor that Kelley was referring to. But there again, I'd say what is "simple" is just what turns out to be more useful in practice. Trying to define any other notion (as Kelley does) is eventually just a definition that may or may not coincide with what people actually do. Basically what I'm saying is that the selection process is done by the community. It doesn't follow from any higher principle, and I don't think it should because in the end we do science for us, and not for a higher principle. Best,

Bee:As Barbara Streisand already told us "Life is a moment in space" and "In love there is no measure of time." Consequently, a universe where time is real must be loveless. I don't like that idea.

Time in happiness seems to run very fast too, and any condensate moments of our emotive states can seem to take longer and longer as we move away from that happiness.

So, if love is timeless, it's not that it doesn't hold any significance it's just that it is indeed a very fast moving world and all seems to flow in a blink of a eye?:)

Bu yes I like your take, as to a matter of fact conclusions about the basis of experience "holding some pragmatic solution in equatorial style."

Isn't this the fundamental of the logic of one's take about life, although, it is very conducive to the basis of a statement equatorially about the truth of things. You say you are not a philosopher, yet, the runs of some of the problems of mathematics can only take one so far as long as a solution is not found? The edge of reason? You then have to make sense of the equation before it can be taken any further and further to this a solution to the problem.

Conclusion:The state of mind of the observer plays a crucial role in the perception of time.EinsteinOn the Effects of External Sensory Input on Time Dilation." A. Einstein, Institute for Advanced Study, Princeton, N.J.

The acknowledged US national debt has passed $13 trillion - more than the US GNP. If the universe is 13.7 billion years old, said debt was generated at an average rate of $949/year.

Borrowing from climatology, reduce expenditures to the average outlay and all will be well. This is trivially accomplished by taxing overexependiture, plus user fees. If there is no passage of time there is no interest accrued on principal.

Progress arises from surplus. One need only consume all available resources and borrow against projected gain to stabilize a discipline.

In the context of QFT, you're "still waiting for somebody to reconstruct the non-commutativity of annihilation and creation operators."

Not sure what you mean by this, Bee? A&C operators are a mathematical introduction that can be used to construct Hilbert spaces, Fock spaces, which are then used to model physical systems. Alternatively, A&C operators are natural enough, at least if we are "given" quantization of a harmonic oscillator, which extends pretty naturally to a lattice of interacting harmonic oscillators, to which we add perturbation theory. What more than this kind of account (to a pragmatic standard of rigor) do you want for this? Do you have an idea of what would constitute a "reconstruction"?

It feels as if you might have mentioned "tractability" at some point in this post. Alternatively, you might have mentioned "usability by engineers", which I suspect is what ultimately drives acceptance of a theory. What engineers particularly like, I think, is a formalism that is mathematically relatively simple and tractable but that also inspires the imagination of ways to use it --- which are good for Physicists too. Although you say here that "if they make the same predictions, they're the same theory", you seem also to be stepping back a little from the theme of your post that you link to, "Knowledge for the sake of knowledge". I look forward to your elaboration of "usefulness".

I was raised in the school that thought that no good could come from physicists fraternizing with philosophers, and that if they had any sensible to say they ought to be able to write an equation for it.

Regarding measurement process in quantum mechanics, I would like to talk about my view: We can say that QM is actually measurement incomplete in the sense that in QM we don't even know how any measurement can have a definite outcome at all. The collapse process is kind of cheating.Now if a theory as fundamental as QM does not explain how we can have outcomes at all then there is definitely something very curious about it.

Yes, I know what A&C operators are, what role they play and what to do with them. The question I'm raising is why do they have these properties in the quantum theory. Is there another way to arrive there instead of postulating?

Do you have an idea of what would constitute a "reconstruction"?

No. I just think why the quantum is a more interesting question than why the measurement. Best,

I was raised in the school that thought that no good could come from physicists fraternizing with philosophers, and that if they had any sensible to say they ought to be able to write an equation for it.

Oh, we went to the same school?

I used to feel the same way before it dawned on me that professors weren't always right. Philosophy has always influenced physics, however the two grew apart once the mathematics began to get beyond that which was taught in Philosophy schools, ... sometime around Herman Weyl (early 1920's).

From Philosophy, Physicists learn to question their assumptions.

From Physics and its mathematical language, Philosophers learn how simple axioms can develop into complicated and complex systems. If they understand the math, Philosophers are in an excellent position to tie it all together.

Unfortunately there is way too much BAD philosophy out there. It gives the profession a bad name. But it never hurts to remind ourselves of our intellectual heritage, that Philosophy is essentially Aristotelian Logic; that from Logic sprang both Mathematics and Science; that science was once called "Natural Philosophy", i.e., Applied Philosophy.

Words, semantics, etc. It's all of a bit of a blend in the end. Interdisciplinary approaches to solving any challenge or mystery seem to be increasingly employed, perhaps because they are needed. But let's be careful at the same time, as "going interdisciplinary" can get carried away with itself into nonsense by slick-tongued devils.

I get the feeling that was not the case at Perimeter. Good show all around. Good Philosophers are worth their weight in gold; bad ones are hired by FOX News.

"I was raised in the school that thought that no good could come from physicists fraternizing with philosophers, and that if they had any sensible to say they ought to be able to write an equation for it."

Well, I would argue then that before you can write down an equation all is philosophy. I think the pre-equation stage is important for science, thus I see a benefit in such an exchange. Best,

Though I appreciate your position I think to a certain extent even the most pragmatic of researchers can’t deny carrying around with them a sense of how nature reveals itself, regardless if they find it can be explained reasonable or not. That is things like symmetry and conservation being perhaps the strongest of what’s recognized as such signposts. The thing is of course both can be expressed mathematically and have been shown to be intimately linked to each other within its logical framework. In such regard I’ve often thought Occam’s razor as the same, only with it being manifest more generally although less definitively.

I never understood how such things could be considered by some as just the overlays of our thought process, rather than something more fundamental. The fact is forms such as the circle does have an invariance under transformation that’s independent of how we think about it, which by way of its symmetry restricts its boundary to being the one of least distance to contain any given area, which in turn is a conservation found prevalent throughout nature whose significance in respect to the physicality of the world can’t be denied. Rather I think to equate such things as the same as finding forms in a cloud gives an ability to mind that just can’t be justified. That is I find these days a lot of thought is given to how process can be seen to dictate form, with less thought given as to why so many processes lead inevitably to the same form.

In the similar manner I find that many take Occam’s razor to mean that nature is simple, as to require it contain little or no reason, rather than it having no reason to add complexity that fails in its execution to conserve. So to agree with Pirsig, I find that reality to represent the physical manifestation of quality, where such signposts being simply ways it can be recognized, which from my perspective is the only way they can be connected to being aspects of mind. I’ve always thought Einstein to have expressed this best as to draw the important distinction. There was a time when people of science were proud to be considered as natural philosophers where today it’s held the same by only a few.

"The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience"

Of course I’m sympathetic to your take on matters, except with you laying blame as to it being a consequence of the mathematical complexity found in modern theory. That’s from the perspective of individual intellectual disciplines; mathematicians are in general the more philosophical group. I always found it interesting that at the apex of Bertrand Russell’s brilliant career in mathematics he gave it all up for the pursuit of philosophy. When asked about the switch he said he had finally come to realize how limited in capacity mathematics served as being able to explain the world. I only wished more physicists would recognize the same/

I’m sympathetic to your take on matters, except with you laying blame as to it being a consequence of the mathematical complexity found in modern theory.

But there was a rift between Philosophy and Physics, Phil, and it lasted for most of the 20th century. Events like the one Bee attended at Perimeter are all good in an attempt to re-unite them, or at least to get them to talk to each other, which should lead to the same.

Physics parting ways with philosophy wasn't all that bad though as it turned out, because Physicists migrated to Engineers. Los Alamos, Chicago, and all the great particle accelerators since. The Transistor. Manned Space Exploration. Better Drugs. Physics and Engineering merge.

Physics seems to have hit a wall, Phil, it's a victim of its own success. The real action is in Biology now. The pause it good if physicists use the time to educate philosophers in Physics' ways.

If you're going to bring up Bertrand Russell Phil then I'll have to bring up Buckminster Fuller. Your move.

Hi Bee, "Yes, I know what A&C operators are" --- and I know you know. Sorry.

"why the quantum is a more interesting question than why the measurement" --- I think that's pretty good. To some extent, I think we can take "the measurement" as a given, although if we take this beyond a moderately pragmatic view I suppose we come to something like Positivism. The next step, into Science, of systematic measurements and records thereof, needs us to provide a "system", particularly for us to decide what measurements and records are or might be interesting. We do things systematically because that has turned out to be interesting and useful. "quantum" is one such system. I'm not sure that "why" is a very productive question here, however; I think I prefer "what else might work?" and "what relationship does it have to quantum?", because answers to those give an expanded context in which we can place an answer to "why". I think the attempts to axiomatize QM and classical in a single system have been reaching for something like this.

I noted that you singled out QFT instead of QG here, although I perhaps should expect that with that noted you would assert that we will ultimately have to look to QG for answers about QFT?

The vast majority of conversations I have on this blog are fine. Otherwise I wouldn't continue to write it.

There are two things that occasionally disturb me. One is people who dump here their frustration about their research or ideas not being appreciated by the scientific community. It's simply inappropriate. I'm not the enemy. I'm spending my time here voluntarily trying to communicate some science. The only reason that I can imagine people are doing this is to stop me from having fun in blogging so they can spam the web with one scientist less in their way. Luckily this happens rarely.

The other thing is people who dump their ideas here even though they are completely unrelated to the topic. I'm German. I like things orderly. Random dumping just clogs the comment sections and doesn't contribute to a constructive on-topic discussions, which is why I (and our comment rules) discourage this. Unfortunately, there's many people who seem to think that whatever the comment I must be happy about it. It happens sometimes that a discussion starts one place and evolves elsewhere. That's fine. You have probably noticed that I frequently pick up the new topic in another post. But I could do without people posting random questions (like, recommendations for a textbook, or here's this question I have about SR, or have you read this (I usually have)).

I have to add that the situation has vastly improved since we've disabled anonymous comments.

Yes, I know what A&C operators are, what role they play and what to do with them. The question I'm raising is why do they have these properties in the quantum theory. Is there another way to arrive there instead of postulating?

My guess of an answer to the question "why do philosophers like quantum mechanics (QM) more than quantum field theory (QFT)" would be that QM is "fully understood" in a mathematical sense, QFT is not, and QFT does not add any new philosophical problems, the problem of the interpretation of quantum systems are all there in QM. (That is not my opinion, it is a subsumption of what I observed).

About the question if A&C operators and their commutation relations could be reconstructed from something more fundamental: Interesting question! I don't know. In the framework of axiomatic QFT due to Araki-Haag-Kastler the Reeh-Schlieder theorem says that there cannot be a localized particle count operator, and therefore no localized creation and annihilation operators, see for example Stephen J. Summers: Yet More Ado About Nothing: The Remarkable Relativistic Vacuum State.

Of course you do not have to agree that the Haag-Kastler approach to QFT is correct, but maybe, on a more fundamental level, the usual notion of 'paticle' does not make any sense anymore and A&C-operators don't either.

(c) Mathematics reveals that, if particles are indistinguishable, a theory of an arbitrary number of particles is the same as the quantum theory of a linear Schroedinger field. A&C operators appear here by analogy with the harmonic oscillator, which is also linear.

(d) Infer that some fields should be quantized.

(e) Inference is confirmed by successful explanation of the odd behavior of known fields.

(f) Infer that all fields should be quantized.

(g) Mathematically classify all fields and try to quantize them: work in progress.

(h) Check inference by using both new and old fields to explain new observations: so far so good.

Araki-Haag-Kastler and generalizations aim to mathematically classify all that is known from (g). Their mathematical framework is justified by the chain of inferences (a)-(f) and meets the usefulness criterion as long as (h) continues to hold.

The question is why quantize? Note why, not how. Is there a way to understand it instead of postulizing, that's my question. We just know that 2nd quantized theories are more fundamental, so it's kind of a mystery to me why bothering with qm as you might worry about features that are a consequence of not using the fundamental theory to begin with.

Should probably clarify: we of course don't know that 2nd quantized theories are "the" fundamental description of Nature, point I was trying to make is that we know they're more fundamental than 1st quantized quantum mechanics.

Both first and second quantized theories use the same quantum formalism. So, if one is interested in some feature of this formalism, either kind of theory is fine to use as a toy model. It happens that particle QM is easier to work with than field QM.

I understand your concern, however I do not see much evidence that it is warranted, but perhaps you do. Are there any specific examples that have made you worry about this?

The formalism differs in the interaction, and what is a measurement if not an interaction? No, there's no specific reasons, it's just that sometimes one has to make things more complicated before they become easier, so I'm wondering if not looking at 2nd quantized theories might yield more insights. But as you know, it's not a field I'm working on, it's just a thought that comes back to me whenever I hear somebody talking about reconstructing quantum mechanics. Best,

Sorry, but I don't know what you mean with "quantum is a system". Fundamentally, all systems are quantum, it's just that with most macroscopic systems the effects are entirely negligible. The question "why" I'm asking is basically the question whether the quantization procedure is really fundamental, or if it will eventually been shown to be derivable from more fundamental concepts. And yes, it might be that we'll have to look at qg before we can fully understand qft, but it might equally well turn out not to be necessary. Or at least I don't see why it's necessarily related. Best,

I agree with your assessment why qm receives more attention in that respect than qft. Except possibly for the problem of renormalization which seems to spark philosophic thoughts as well. Unfortunately, the gap between philosophy and science rapidly increases the more difficult the techniques are. Thus, I am afraid the more advanced physics becomes the less useful philosophers become, simply because most of them (there's of course exceptions) are limping dramatically behind or, worse, not able to follow the maths cling to superficial analogies. Best,

Thus, I am afraid the more advanced physics becomes the less useful philosophers become, simply because most of them (there's of course exceptions) are limping dramatically behind or, worse, not able to follow the maths cling to superficial analogies.

It is then as Einstein reminded to have the physicists do the philosophizing as “they know best, and feels more surely where the shoe pinches”.

Bee, forgive my relentlessness. ;) I often use QM and QFT interchangeably in my mind when thinking of issues pertaing to the quantum formalism. So, if there is a potential trap there, I'd like to avoid it.

What do you mean by "differs in the interaction"?H = H_0 + H_i in either QM or QFT.

I was wondering if your own boxparadox got any play or review at this past conference. I believe it to be more far reaching then just what you initially were having it to demonstrate in respect to invariance,

Being superficial as Ursula Goodenough points out, contains the possibility that you could be fooled by appearance?

What is Information?

Then let’s try to identify what information IS, with the specificity of organized processes, given a “relevant description of processes”, in some part of the world. Note that we have a semantics automatically: the constraint “means” the enabled organized process. And we automatically link matter, energy and information. (We can get to human communication and the web in a later blog.)

But this brings us to where these aperiodic crystals and diversity of enabling constraints come from. Marcelo spoke of asymmetries in an earlier blog. I think he is deeply right.

The universe presumably started as an essentially homgeneous ball of energy and maybe quarks and gluons and expanded and cooled and broke symmetries.

But broken symmetries can be a source of free energy, enable work to be done, and can break more symmetries.What is Information

Bee, I'm not sure I appreciate the distinction. Perhaps I see a more general unifying picture, while you see distinct examples.

The interaction H_i could be an arbitrary operator. Both the 2-particle Coulomb interaction in the Hydrogen atom and the current-vector potential interaction term of QED are special cases. I can think of a number of features distinct between these two kinds of interactions. However, for each feature, I can think of examples from both QM and QFT that exhibit the same feature (or both lack it).

Yes, I know I'm being quite vague and general in the above statement. However, if you name the differentiating feature you had in mind, I can be more specific.

From my understanding the distinction between QM and QFT, is that the latter is an extension of the first for which invariance had to be incorporated as a key aspect of the theory. In order to have this accomplished it became imperative to incorporate mathematical techniques and practices, that although practical in terms of moving things forward, have never been given adequate reason as to how they work in respect to the problem presented and overcome. I would agree it is such avoidance that is in part largely responsible for the current dilemma and why it is then useful to take things back to the beginnings to find if something important has been misinterpreted, over interpreted or simply overlooked.

I think then if physics currenly is a victim of anything, it lies with its own impatience. This becomes abundantly clear when so many alternative approaches look to be as equally sound. It is hard to use Occam`s razor when one can`t have distinguished what stands as being a consequence of nature or a consequence of theory. Thus I find this not a time to imagine how nature might be as it is, yet rather a time to question our fundamental notions in such regard. The most dangerous of notions being if it works it`s unimportant as to the reason it does, as in my humble opinion finding reason in nature being the utility of science. Cycles and epicycles and orbs within orbs might make great bedtime stories and yet hold no semblance to being science, for although lending a way to predict outcome, they in the end describe a reality that doesn`t stand to represent the one it was meant to .have understood.

From yet another perspective, would you not agree it strange how many find it so surprising that mankind has not as of yet come up with a adequate QG theory, while many of its best and brightest still struggle to find a way to shut off a leaky pipe at the bottom of the ocean:-) It is times like this I am both amazed and amused by the depth of human arrogance.

The question whether the first quantization is really fundamental, or if it will eventually been shown to be derivable from more fundamental concepts, has qualitative answers only, mostly based on the concept of finiteness of information. (Maybe we all must first read the 'Essay on Non-Teleological Thinking' by John Steinbeck.) http://www.metanexus.net/ultimate_reality/zeilinger.pdfhttp://arxiv.org/abs/quant-ph/0212084http://www.metanexus.net/Magazine/tabid/68/id/5865/Default.aspxhttp://arxiv.org/abs/quant-ph/0402149

Two things. One is that the interaction is one though not the only difference between qft and qm. The other is that what I meant is simply do you or don't you quantize the gauge field (interaction). In qm, V is a scalar function (that's some sort of operator, but a trivial one), in qed the interaction term in psi^\dag A \psi and A is an operator, not a c-function. Let's leave aside for a moment background field methods, this only makes the water muddy. As I said above, I don't know if that's relevant for anything, but I'm wondering how one can ever understand the measurement process if one doesn't use a correct description of interactions and particle FIELDS to begin with. After all, a measurement is an interaction. One could of course say that the measurement process is just some effective description anyway, so maybe it doesn't matter after all. Best,

I'm not sure what you mean with "invariance" here, but I think you might be confusing something. The qft's that we use today are gauge invariant (and Lorentz invariant for that matter), but you can also have gauge invariance (and Lorentz invariance) in classical theories (electrodynamics for example). The standard textbook explanation you get for the difference between qm and qft is that the latter allows for particle creation and annihilation which eventually necessitates the need to build up a multi-particle space from the one-particle space. That's the above mentioned Fock space and it's built up most conveniently by use of the "annihilation and creation operators" that I was referring to. That's all very technical but roughly these operators do what their name says, they annihilate and create particles. Best,

With regard to your other comment: no, my box paradox didn't play a role in this conference. It doesn't really have to do anything with the topic. I suspect it will come up on our July workshop, read Lee's abstract. It's still rather unclear to me whether it will eventually lead somewhere in the sense of being constructive for an improvement, or whether it's a death spell. Best,

I think that simplicity, usefulness and also abstractness are very context-dependent notions that change over time. It is thus not very meaningful to raise them to an absolute standard. See, what we consider "simple" today might have seemed enormously complicated to people 500 years ago because they were lacking all the previous knowledge and education that we can build upon today. But yes, I would agree that a high level of abstractness makes things more complicated in that it's significantly harder to make improvements. On the computational side, abstractness does not matter much (shut up and calculate), but if you can't really understand what you're dealing with it becomes harder to creatively work with it. Best,

Phil wrote:From my understanding the distinction between QM and QFT, is that the latter is an extension of the first for which invariance had to be incorporated as a key aspect of the theory.

The best IMHO characterization of QFT is that it is QM with special relativity. Bee explained already that QM does not know particle creation or annihilation. QFT has to include this because special relativity says that matter is just a manifestation of energy, E = mc^2. That's what "second quantization" does, it takes a state space with fixed particle number and builds a state space with states that include all possible particle numbers (that's the Fock space). A second aspect is causality: QM has signal propagation that is faster than c, QFT has not.

It is of course correct what you say, but it's slightly confusing in that relativistic quantum mechanics is nicely Lorentz invariant. It's just that it leads you to conclude there have to be antiparticles, and it follows the whole Dirac sea and hole theory story. Best,

I’m somewhat surprised that you would refer to QED as a classical theory or do I misunderstand you. In respect to invariance I use it in the most general sense, as it being an aspect of symmetry rather than any particular recognized manifestation of it, such as Lorentz or gauge. I understand what you’re saying with classical theory containing invariance, with that being the case long before Einstein. Yet when such concepts were forced upon QM techniques were introduced that although solving certain difficulties were never solidly grounded in the theory from the physical side of things, as to what has such techniques to be valid beyond the fact that they worked.

In part that was Bell’s complaint about SR, in it invoking symmetry upon nature without building up a physically grounded sense of its action. I guess what I’m saying is that we don’t understand the role of symmetry in theory beyond it being present as to have consequences for them. These then are the places I still find room for philosophers such as Unger in their attempts to explore the foundations right down to the initial bricks., He and Smolin now propose time as being such a brick and it will be interesting from there how they propose to build reality, including all its aspects of symmetry.

"Though I appreciate your position I think to a certain extent even the most pragmatic of researchers can’t deny carrying around with them a sense of how nature reveals itself, regardless if they find it can be explained reasonable or not. That is things like symmetry and conservation being perhaps the strongest of what’s recognized as such signposts."

That's not the point I was making. As I have said for example recently in my post Terra Incognita it is of course true that some scientists form some picture of Nature, an intuition of what works, that they more or less come to rely on. Some of these pictures are more successful and those are the ones that are wide spread (like currently symmetries). Good scientists remain flexible with changing their pictures. But point I'm making is that while this may be a way how people pursue their research, and other's don't (I do indeed know scientists who are *very* careful saying that they don't believe in any fundamental truths), what matters in the end is not how they arrived at a theory, but whether the result is useful (and as such justifies their procedure to arrive there as useful). I hope the difference is clear: I'm not saying that scientists do not carry around pictures or intuitions. I'm saying what matters in the end is if it works, and the rest is memoires. Best,

That’s what I thought you meant, yet having it as initially Lorentz invariant left me confused, unless of course you meant Einstein had it made clear that it was necessarily so by way of not making the distinction within its formalism. Einstein’s central contention being Maxwell’s theory implied ithe invariants presence, which Lorentz, Poincare and Fitzgerald also recognized and yet took to have its action satisfied within the context of maintaining a fixed reference frame. Today for most physicists such distinctions are moot points and that you could say is what my point is.

I hope that you’re not under the impression that I’m attempting to have you portrayed as one those for which I have compliant, yet rather quite the opposite as I find that you tend to shy away from making assumptions as to blindly have them defended. For instance what Smolin refers to as your paradox is most indicative of this, as it being based on the most physically fundamental assumptions which in contradiction beg for an explanation that tends to have it required either certain current assumptions be dropped or more long standing notions re-examined. So I would say despite you seeming to shun being so described you are a foundationalist.

Bee, I see more precisely what you mean now. Allow me to rephrase your question: Is it possible to study the measurement problem within QM, given that all interactions are limits of coupling terms in QFT (like the QED one you cited)? I believe that the answer is yes and that is actually being done in physics research, though I don't know enough to say the same about philosophical research.

A coupling of the form (psi* A psi) can be modeled in QM, say, by two oscillators x and y with a coupling terms like (xy+yx), (xyx), or variations thereof. In fact, these kinds of interactions are precisely the kind used to model measurement and decoherence processes. A well known example is the Caldeira-Leggett model.

The idea of reduction from QFT to QM is to keep the key features of the problem and throw away as many complications as possible. A priori, it is not obvious that such reduction is possible. However, existing work shows that in many cases it is.

When it comes to your own work my happiness holds no relevance as they are your “happy thoughts” and not mine:-) None the less I’ve been exposed to your thinking long enough to know you are most annoyed when someone superimposes their own thoughts as to being yours, that’s to agree pragmatism shouldn’t be confused as to be considered a limitation to new ideas, yet merely a qualifier of them.

Well, actually I'm not too interested in the measurement problem, as I wrote in my post. It might well be that to that end qm is sufficient, but the question is whether along the way you're throwing out another important feats of qft that eventually prohibit a real understanding of the quantization procedure. If that doesn't seem to make a lot of sense it's probably because it doesn't make sense ;-) Best,

Picking an issue was a case in point I think and trying to follow it through as to what a scientist may hold in front of "their senses" as to what could account for some description of the world around us and how one may interpret that process they choose.

Over the years one of those issues "was time" in regards to Lee's thinking, and another is of course "symmetries" as had been relayed through this blog many times.

Still a lot to learn but I am enjoying getting up to speed with the knowledge that you are sharing.

Hello Bee, there is a question here!In his FQXi essay Julian Barbour questions Newton’s time and demonstrates that, with a clever cast, one can remove time from a dynamical equation. He concludes thereby that time must be an emergent rather than integral feature of nature. He states, “Time emerges only on the extremal curves (of the least action transition between the fixed end points of two possible configurations of the universe).

If his essential point has not suffered too much in my translation, I find myself quite willing to give up on Newton’s time, but still very much attached to mine own. After all, an emergent property may be a very useful and real property, real enough to set one’s grocery bags upon at least, and surely time was up early at the dawn of creation. I doubt much really got done before time clocked in. Yet perhaps Dr. Barbour means to do away with time altogether. I expect he is probably correct, certainly more than half way.

In the Dutch video, “Killing Time”, Julian illustrates Newton’s time by holding up a little drawing of laundry pegged to a clothesline, the idea of a linear, metronomic progression upon which we can locate past, present and even future moments. Perhaps a major flaw with this type of time is that it is disjunctive, it is a generally applied rule and it lacks direct relationship to nature’s underlying terrain. What if time’s geometry was more complex, rather than a simple line, what if it is more of a knitted affair, less mathematically comfortable but with more of a personality? In this light Newton’s time is an artifact, yet still a proven tool for the strobe-like illumination of nature along a certain axis.

Nature has what it needs. If it needs time, it probably calls it by another name. Does our science need time to treat with nature? I would say yes, because periodic phenomena vary throughout nature, in both phase and scale, by greater than thirty orders of magnitude. If the distance between points were declarative of a need for space-like dimensions, then the difference between phases would be declarative of the need for a time-like dimension. Timing matters in any enterprise, the valve closes, then the spark of ignition.

As to time’s emergence, if we keep in mind Julian’s “fixed” end points and the curve of least action (the “change”) between them, here is a curious construct.Consider a tale of two houses in some province of long ago. These houses are utterly at odds in their nature and each one is without time. The quieter household is governed by stasis; all things are “fixed”, no one-thing changes, and no little shift of tick to tock. What need for time if no thing changes?Now the other house, in complete contrast, is an unruly bedlam of change so savage and continuous that there is no enduring clock, no memory of tick or tock. What need for time if no thing endures?Now say that, some enchanted morning, there is an alchemical conjunction, a marriage between these diverse households from which a new thing emerges, one that acknowledges the natures of both parents. What child is this?

I'm not sure I understand your question. If you have a curve that represents time and the curve is self-intersecting ("more of a knitted affair") you cause all sorts of problems with timelike closed loops. Basically you're completely wrecking causality. Best,

"It is very good that Stu Kauffman and Lee are making this serious attempt to save a notion of time, since I think the issue of timelessness is central to the unification of general relativity with quantum mechanics. The notion of time capsules is still certainly only a conjecture. However, as Lee admits, it has proven very hard to show that the idea is definitely wrong. Moreover, the history of physics has shown that it is often worth taking disconcerting ideas seriously, and I think timelessness is such a one. At the moment, I do not find Lee and Stu's arguments for time threaten my position too strongly."- Julian Barbour Bold added for emphasis by me

Also.....

Julian Barbour

In my "The End of Time" I argue that the wave function of the universe is static and that the appearance of the flow of time emerges because the wave function of the universe is concentrated on configurations of the universe that we recognize as records. Edward Anderson and I are currently trying to develop this idea and create a theory of records. If successful, this work promises to explain the origin of the arrow of time at a fundamental level.

I suspect this reflects the expectation many people have that time is not fundamental, but rather emerges only at a semiclassical approximation in quantum cosmology. If you believe this then you believe that the fundamental quantities a quantum cosmology should compute are timeless. This in turn reflects a very old and ultimately religious prejudice that deeper truths are timeless. This has been traced by scholars to the theology of Newton and contemporaries who saw space as “the sensorium” of an eternal and all seeing god. Perhaps the BB paradox is telling us it is time to give up the search for timeless probability distributions, and recognize that since Darwin the deep truths about nature cannot be divorced from time.

The alternative is to disbelieve the arguments that time is emergent-which were never very convincing- and instead formulate quantum cosmology in such a way that time is always real. I would suggest that the Boltzman Brain’s paradox is the reducto ad absurdum of the notion that time is emergent and that rather than play with little fixes to it we should try to take seriously the opposite idea: that time is real.

Julian Barbour is adorable. I almost bought his "The End of Time" one day, but skim-reading it in the bookstore, I wasn't quite sure what he was saying or where he was going, and I didn't see what kind of test could prove or disprove his views. He is nevertheless perhaps the number one Independent Researcher in Physics, and I wish him well.

Block time makes all the sense in the world. Which means it may be wrong because so much of physics is counter-intuitive. :-)

I've been re-reading Hawking's 2 popular books, and my objections then remain the same ==> What the heck?! I adore Hawking, but the emphasis on imaginary time vexes me. I had the same feelings about Einstein - I understood Relativity better by reading Martin Gardner's "Relativity for the Million" than Einstein's own book on the subject. Hawking radiation is awesome, but I learn more by reading its description by others. A little math wouldn't hurt.

Retrocausality has been in the news a bit lately. Why, I don't know, possibly an article in Discover. The first time I ran into it was last year's paper by Holger Nielson predicting the future would prevent the LHC from starting up. Oops.

Retro is more philosophy than physics, though. Whatever the true "laws" of nature are, a law is little else than our best guess of a mathematical model describing a part of reality. For example, the 2nd law of Thermo: reading Sean's Carroll's book, I learned than entropy actually can increase, but only by a tiny amount on a very small scale in a very short time, the net effect being zero of positive. Wow.

There is nothing to actually be understood in SR other than the invariance it forces upon nature, mandated by it having a specific symmetry. From this point of view the mathematics is simply a device used to describe the consequences of the symmetry, which itself is a quality of nature whose total description it is incapable of capturing; that is at least from the Platonian perpective:-)

So another issue about BB's and how the universe came into expression....points of view to contend with.

How philosophy and science can work together to set the frame of reference for consideration.

You might say you have no need for philosophy, but imagine if you were helped to ask the right questions?

Reverse chronology — narrating a story, or parts of one, backwards in time — is a venerable technique in literature, going back at least as far as Virgil’s Aeneid. Much more interesting is a story with incompatible arrows of time: some characters live “backwards” while others experience life normally.

Sometimes the exercise in mental flexibility is the effort to move the mind from the position it has always assumed. Thus, the mind then sees things that it is not normally accustom to while holding this new particular frame of reference.

Thanks Bee, In other words, keeping in mind QM’s duality, what do you get when you add something discrete to something continuous? What is the emergent property? What new thing arises that incorporates and contains these disparate parental qualities? I believe nature does the math in answer to its own question: How do you constrain energy within a given frame?Not sure this ball will land anywhere near your court.

In quiet reflection I look at the blog entry of Bee's. It is of interest as to the perspectives that science has bestow upon the layman in general shows how scientists are occupied in mind. But imagine......

Time is of your own making; its clock ticks in your head. The moment you stop thought time too stops dead. Angelus Silesius

Does this mean then that no such thing "as memory" could arise from the future or the past? Imagine the beating of ones chest as to the finality of expression(death) when there is no longer any future or past?

Einstein wrote

"...for us physicists believe the separation between past, present, and future is only an illusion, although a convincing one."

Maybe a grant for the investigation into Time?:) You still have time Bee.:)

I think you're mixing up our conscious (biological, neurological) ability to recall memory and the physical basis for memory. The former might end with death, but the latter doesn't. In fact, there's not even any reason why memory has to be connected to life to begin with. There's certainly materials that exhibit some sort of "memory" and even our planet has some sort of "memory" of the past (think meteoroid craters or so). This is all evidence for the arrow of time, but not commonly what people refer to as their memories, as in recollections of events of their life. Best,

In a nutshell, what Karim showed was that each time a memory is used, it has to be restored as a new memory in order to be accessible later. The old memory is either not there or is inaccessible. In short, your memory about something is only as good as your last memory about it. Joseph LeDoux

I think as shown with Kauffman's investigation into information, there is a substrate "to the actual perception" on a conscious level? On first appearance of the memory, do not be fooled.:)

Some may call that substrate mathematics?:)A closer recognition that we are coming "ever closer" to the understanding of those microseconds of the universe?:)

Some are not content with the universe the way it is and raised the question of "cosmological reasoning" outside of the box thinking. Veneziano came to mind.

Ummm.... Steinhardt and Turok.

BB's then are nothing more then the accumulation of "all the data expressed in new ways?" It's all out there already, we just have to be able to "touch it in some way." So it's all consolidated in one spot, for an expression in a much larger venue again?

I never did understand why so many are shocked and confused to find invariance present in the nature of the world, especially when it involves the consequence of symmetry. For instance if there were ropes that were drawn tightly around both the circumferences of each the Earth and Jupiter (presuming Jupiter was solid of course and both planets actually round).. Should we then be surprised to learn that if we wished that each rope where to sit off the surface of ether by a foot all the way around that the additional rope we would require to add in each case would be exactly the same. This may seem to be counter intuitive yet this is more telling about our intuitions, rather than what such intuition represents being in respect to the truth.

Bee, I surely don’t wish to lessen the general tone here with anything too erroneous or sophomoric, but I am deeply curious.

The question is: What do you get when you add something discrete to something continuous? What new thing emerges that is both discrete and continuous?

A more or less proper mathematical answer would be the compactification of a line on a point producing a circle, the circle being both discrete within a larger space and continuous in its perimeter.Nature works the sum in myriad fashions, the prototypical example being the rock in the stream with the omnipresent eddy. The cyclical pattern is a path of accommodating contrasting natures.

So, long story short, given that nature seems behave both discretely and continuously, is the cycle deeply seeded in nature at the level of some fundamental geometry?It seems as though the cycle would be requisite for structure, a means to insure that energy doesn’t simply wander off the page.Regards,

Time: The notion of time as changing due to the speed of travel is a misguided concept. It is accurate in theory, but not in fact. My Theorem: “Time is immutable, just as space is. Both are underpinned by infinity and quantum mechanics, which dismantle classic mathematics and physics as we might hope to simply define them.” This is a simple theorem, that speaks clearly for itself. In other words “time and space” are fixed and outside of our finite understanding. They do not change, as “Special Relativity” implies, by curving or slowing down or speeding up dependent on speed and mass. They can be described as such in a quasi-manner, but in fact they remain as they are. Infinite and inexplicable.

The current understanding of time is based on mass and velocity, or Einstein’s Special Theory of Relativity, but time is again, as I said immutable, and subject not to the speed of an object, relative to its mass, but to its mass alone, subject to gravity. In other words all objects will not slow down or speed up based on the speed by which we travel. The current experiments that use atomic clocks: One clock stationary and the other traveling at high speed and then are used to measure their times which are logically different, is fatally flawed. Time is effected by way of atomic clocks, simply by the gravity or mass it experiences within its travel. Again in other words, if a clock is traveling at a high velocity, it experiences greater gravity in a shorter period of time, which alters its mechanical functions. Time does not actually change only the forces of gravity that impact its mechanics changes. Thus slow down or speed up its time actuations. Time remember is immutable. [Period]

Time and Space when defined within the framework of “Infinity” are non-starters. They do not really exist. The Alpha and the Omega are finite terms, not terms born from “Infinity”. Infinity by definition can have no “Beginning” nor and “End”. It is by definition “Incomprehensible”. So SpaceTime, or Time and Space, and so on are again, capable of description within this relam as simply “Everything” and “Nothing” existing at the same time. There is no space and there is no time, and yet there is. That is the simple definition of infinity. Hence indescribable. Remember, if it were describable, it would be circumscribed, and hence no longer infinite. One of the few absolute truths – I know…

However Time and Space within the finite world of objects is inescapable. It is by finite convention or application, a fact.

IN CONCLUSION: In one world or dimension: “Infinity” Time and Space does not exist, but in the other “Finite” world it does exist. NOTE: Save “Entanglement” which is a glimpse into the infinite, which I believe has to do with “Wave” vs. “Particle” science.

So the Holy Grail of unification of science (Realitivty/Quantum) is a mis-quided notion. It is worthy of seeking, to uncover new science, new truths, but it is an infinite quest, that cannot, and will not resolve its duality. You are either One or the Other. And never shall the twain know the other. This is what makes the world go round. But mankind refuses to give up on some bigger picture, that controls our destinies. Hence religion, culture, belief systems struggling to understand time and space, as if they were understandable. They are understandable within the context of their own dimensions, either infinite or finite. But that is all folks…

Thank You for your review of Time, this is a great forum, I regret I am so verbose – I know well!!!

I have other ideas about Energy and Time @ www.otterwrite.blogspot.com Russ OtterEmail: russ@otterworks.comJune 2010

Will try to be brief (terse?):1. Fabulous Blog. Just shows that in spite an apartheid between Physics & Philosophy, we do enjoy intramural donnybrooks.2. All Polemics can be reduced to Semantics (Wittgenstein?).3. Shut up and Calculate (Feynman?)4. Never mind A&C, QFT etc.; what is a Wave function? The old saw,A dodge to fudge over Young's Expt & Photo Electric effect except 3 above (it works!).5. For an Applied Physicist (thus a humble Physicist) 2+2=4, Try reverse engineering 4=?. Infinite # of solutions (-ve #'s allowed). All of them equally valid. We get data & then try to shoehorn it into theories, from sensible to bizarre. All of them equally valid, if 3 above.6. Some of the papers on Philosophy of Physics may remind one of the Sokal affair. Try to enjoy Shakespeare by reading its 'Deconstruction' authored by an eminent tenured English Prof.

Be it resolved, a dialogue between Physics & Philosophy is a most entertaining Polemical Firework (2 above)? A. Choudry

The issue is whether the universe is a block (all times exist equally) or if presentism is correct (only the present exists). I would say no experiment can demonstrate the existence of the past or the future, since experiments happen only in the present. So the block conception should be abandoned.

I think your statement is useless since "existence" is an ill-defined concept. I recommend you read my post on the block universe. The block universe is the presently most widely accepted view of our world because Special Relativity prevents you from defining a naive notion of simultaneity from equal time slices. Best,

I read you blog on the block universe. As you know, light signals allow you to infer they had a source at some past time in some place, not that there is a universal notion of simultaneity. Yet, as you pointed out this does necessarily lead to the block universe. I just wanted to say that, further, there is no experiment that could prove the block universe, since an experiment exists only when and where it exists and not at other times.

Hi Bee,I am just a mechanical engineer from Brazil, so try to forgive the (probably) stupid things that I am about to say. Regarding the discussion about the meaning of time ... As far as I understand what causal dynamical triangulation (CDT) is all about, time is generated (as well as 3D space) from basic fluctuations at the Planck scale, where time itself has no meaning. In reality the generation of a 4D time-space from basic principles is one of the most interesting and successful aspects of CDT. Therefore, based on what CDT has to say, if you look at the very basic laws of nature there is no time at all, although maybe one can argue that the introduction of causality corresponds in some way to a kind of time arrow. In my opinion more daunting than that is the other extreme of time reality, namely how sentient beings like ourselves perceive time through our conscious mind. We know nothing about what consciousness really is. It seems that, from the Plank scale up to the conscious mind perception of it, time phenomena grows through layer upon layer of complexity and a real comprehension of it has to involve a type of approach that at least I have never seen before, maybe involving models close to Kauffman's and the Santa Fé Institute ideas. From no time at all to our perception of it. Well ... this is just my two cents on the subject. Again forgive me, but I was kind of bored today and just felt this strange desire to see if I still can write something in English that does not start with Hello Mr. X and ends with Sincerely yours. :)

You are mixing up two different things: the emergence of time itself and the emergence of the arrow of time. Not the same thing. I suppose to get an arrow of time you either need to explicitly distinguish between the forward and backward direction (in conflict with the fundamental laws being time-reversal invariant) or you chose initial conditions with low entropy (raising the question why this initial condition?). But once you have that I don't think it is a large mystery why we perceive an arrow of time. You don't have to bother with messy things like human consciousness for that. Very simple systems, like certain sorts of molecules, exhibit some sort of "memory." I wrote a blog post about this at some point: Every Now and Then, that you might find interesting. Best,

Hi Bee,I will try to clarify a little bit more what I tried to say ... again, be patient with my limitations in this field (and my limitations in English also :). I have read that some sort of theories similar to causal dynamical triangulation (CDT) existed before that did not distinguished between the quantum configurations at the Plank scale and that did not resulted in reasonable physics also. The success of CDT was exactly the introduction of causality that makes the next configuration of quantum fluctuations be a direct consequence of the previous configuration. It sounds to me that in some way it corresponds to a distinction of past and future although there is really no time involved, and that the 4D time-space that we know just appears when we zoom out of the Plank scale to larger scales. Regarding the topic of consciousness, beside the fact that we really have no clue how to assemble inert mass and make it understand by itself that it exists, it seems to me that it is important also to close the cycle since the so called "Observer" plays an important role in Quantum Mechanics, where time is part of the fundamental description of nature. Therefore, we start with quantum fluctuations at the Plank scale with no time involved, this generates the usual 4D time-space where Quantum Mechanics dictates the outcome of events, and that in turn is affected by the presence of an "Observer" that one can argue corresponds to a conscious mind of some sort. And again applying the quantum concepts to CDT results in the timeless fluctuation at the Plank scale that generates everything else, therefore going full cycle. To me it seems that we know bits of what is involved but an integrated theory of time is still missing, and what we miss the most is on the side of Observer role in Quantum Mechanics. Remember, if the Observer corresponds to a conscious mind of some sort, it not only is a consequence of Quantum Mechanics rules but it also affects those rules, making the whole thing a kind of non-linear messy system that I have never seem a model for it before. Again, this is just the personal vision of a Mechanical Engineer that from time to time reads amazing things about what people like you are doing and try to make sense of it (and probably fails miserably in this endeavor :)